Kazi Nazrul Islam (Bengali: কাজী নজরুল ইসলাম) (25 May 1899–29 August 1976) was a Bengali poet, musician, revolutionary, and philosopher who pioneered poetic works espousing intense spiritual rebellion against orthodoxy and oppression. His poetry and nationalist activism earned him the popular title of Bidrohi Kobi (Rebel Poet). Accomplishing a large body of acclaimed works through his life, Nazrul is officially recognised as the national poet of Bangladesh and commemorated in India.

Born in a poor Muslim family, Nazrul received religious education and worked as a muezzin at a local mosque. He learned of poetry, drama, and literature while working with theatrical groups. After serving in the British Indian Army, Nazrul established himself as a journalist in Kolkata (then Calcutta). He assailed the British Raj in India and preached revolution through his poetic works, such as "Bidrohi" ("The Rebel") and "Bhangar Gaan" ("The Song of Destruction"), as well as his publication "Dhumketu" ("The Comet"). His impassioned activism in the Indian independence movement often led to his imprisonment by British authorities. While in prison, Nazrul wrote the "Rajbandir Jabanbandi" ("Deposition of a Political Prisoner") and condemned Islamic fundamentalism, orthodox traditions and bigotry in society. Exploring the life and conditions of the downtrodden masses of India, Nazrul agitated fiercely for their emancipation.

Nazrul's writings explore themes such as love, freedom, and revolution; he opposed all bigotry, including religious and gender. Throughout his career, Nazrul wrote short stories, novels, and essays but is best-known for his poems, in which he pioneered new forms such as Bengali ghazals. Nazrul wrote and composed music for his nearly 3,000 songs, collectively known as Nazrul geeti (Nazrul songs), which are widely popular today. At the age of 43 (in 1942) he began suffering from an unknown disease, losing his voice and memory. What was later diagnosed as Pick's Disease, caused Nazrul's health to decline steadily and forced him to live in isolation for many years. Invited by the Government of Bangladesh, Nazrul and his family moved to Dhaka in 1972, where he died four years later.